1. Technical Field
The present disclosure generally relates to securing data, and more particularly, to securing data associated with a digital media device using an encryption key.
2. Description of the Related Art
A storage device, such as a hard drive of a digital media recording device, can be used to store media data associated with received audio and/or video content. For example, one such digital media recording device is a digital video recorder (DVR). A DVR application executed by the DVR provides user interface screens that can be used to manage the media data stored to the storage device. The DVR application can also be used to playback recorded media at a later time, while also having the ability to pause, rewind, and fast-forward through the recorded media.
The media data stored to the DVR can be encrypted in order to protect the media content from unauthorized playback. A secure microprocessor can be used to protect the encryption keys that are used by DVR encryption processors to encrypt the content. The secure microprocessor includes a private key stored therein, useful for decrypting data encrypted using an associated public key. The secure microprocessor can also be used to generate a content instance key of suitable strength to encrypt the media data on the storage device. The content instance key could be a random value (or passphrase, etc.) for example. The content instance key is then encrypted using the secure microprocessor's public key and stored on the storage device in association with the encrypted content and any other digital access rights elements.
Upon request for playback of the media content embodied in the media data, the encrypted content instance key associated with the media data is retrieved from the storage device and decrypted by the private key of the secure microprocessor. The media data can then be retrieved and the content key can then be used to decrypt the media data for playback.
However, because the encrypted content instance key is associated with the private key of a particular secure microprocessor, when a DVR fails it may not be possible to access the secure microprocessor to allow decryption of the stored content from the failed DVR's storage device. Thus, a cable subscriber's library of recorded and encrypted media content becomes inaccessible for playback. This may be so, even though the user may be legally entitled to play the media content, e.g., after paying for that right. Additionally, tying the media content to a particular DVR introduces problems with respect to the sharing of digital media between devices. For example, in some cases, a subscriber may be authorized to view content recorded by a first DVR within the subscriber household on another, second DVR within the subscriber household. However, because the encrypted media content is tied to the secure microprocessor in the first DVR used to record the media, such sharing becomes difficult.
Further, subscribers to media services, such as cable-television, among others, may be authorized and de-authorized for the viewing of media content based on a subscriber's subscription status. For example, this change in authorization may be carried out through the transmission of media access signals from a cable-operator's head-end system to an associated set-top box. However, these media-access signals may simply set a flag or other non-secure logical switch within the set-top that allows or disallows the specified service. However, those wishing to steal the service may be able to easily overcome such trivial barriers, allowing the media data already stored on the DVR associated with the set-top box to be accessible.
Therefore, what is needed are systems and methods that can potentially address one or more of the aforementioned deficiencies.